A New Destination: Beijing’s Rail Line Sets Model for Ultracapacitor Energy Storage

A New Destination: Beijing’s Rail Line Sets Model for Ultracapacitor Energy Storage

August 01, 2016 | Jessica A. Baris, Communications Specialist and Copywriter
Ning Chen has a clear childhood memory of the deafening noise made by trains as they screeched to a stop in Beijing’s rail station.

Chen, Maxwell Technologies’ director of business development, says that reduced noise is one of various benefits of implementing ultracapacitor energy storage in Beijing’s rail line.
Maxwell recently announced that China Railway Rolling Stock Corporation (CRRC-SRI), China’s largest rail vehicle manufacturer, is leveraging Maxwell’s 48-volt ultracapacitor modules in two sets of regenerative braking energy storage devices for the system’s No. 8 line, which runs north-south through China’s populous capital. Regenerative braking is a unique capability that ultracapacitors provide, compared to the less energy-efficient braking mechanism of most rail systems.

"Trains need an incredible amount of energy to start up and accelerate, and they burn a lot of energy when they come to a stop," says Chen. "Ultracapacitors save a considerable amount of energy because they are able to provide the power needed for efficient acceleration within 30 seconds and also have the ability to capture, save, and reuse energy that would otherwise dissipate as heat."

Recovering energy to the ultracapacitor energy storage system is a complete departure from the norm in today’s rail systems. Traditional braking systems, as Chen explains, create excessive friction—and subsequent heat and noise—because they use braking pads to reduce the train’s speed. In addition to substantially reducing noise and heat, ultracapacitors recover energy as the train slows down, helping to smooth out the grid power supply to the train.

"The only device in existence today that can enable these energy-saving mechanisms is the ultracapacitor," says Chen. "Ultracapacitors are contributing really unique capabilities in this application, and are also having an important economic and social impact in terms of cost-savings and making improvements for the environment by essentially recycling energy."

The project is the first commercial subway wayside energy storage system for CRRC-SRI and Maxwell in China.

"Many cities in China have been waiting for Beijing to take a step in this direction," says Chen. "The commercialization of ultracapacitor regenerative braking energy storage has opened the way for this technology to become the Chinese standard for subway energy recovery."

Readers interested in the project announcement may access the press release here.

Jessica Baris is communications specialist and copywriter at Maxwell Technologies and enjoys telling a good story. Her background includes writing and editing for the high-tech, construction, and meetings and conventions industries. A San Diego native, Jessica earned a Bachelor of Arts in linguistics from the University of California, San Diego and a Master of Arts in rhetoric and writing from San Diego State University.

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